Klever

After some experiments with recent improvements of EMG, it turned out that specification for category tty_operations isn't accurate. Some fixes were made in 32397a5 (branch emg-improvements), but it seems that EMG still doesn't invoke some callbacks from containers of such the category. At least this is the case for tty_operations.close and tty_operations.hangup. I used container guards and there wasn't the registration pattern.

In addition, it would be great if you will add corresponding test cases if existing ones don't demonstrate issues.